Hole appeared in leather coral

[lucas_is_here]

Hello this is my cabbage Coral it has been pretty happy for a long time but just today I’m noticing this gaping hole in the coral and the only thing I think that’s temporarily change In the aquarium is the flow, and that is because I have a acclimation box with a fish that needed to separated so it is changing the flow pattern a bit. Could that be the reason this hole appears or is a pest? It seems to have these white shaving looking things near the whole I’m not sure what that is someone please help and advise what I should do

 

[Ben.QLD2]

You will need to post white light photos to be of help, but I can make out tissue necrosis. Probably no way back from that.

 

[lucas_is_here]

You will need to post white light photos to be of help, but I can make out tissue necrosis. Probably no way back from that.

Here are photos with flash I hope this helps a little better

 

[Ben.QLD2]

It's definitely necrosis. The only time I had this happen to a leather was many, many years ago when I ran halide lights and the glass lamp screen broke and exposed the leather to much harsher light than usual. Over the next few days it started looking like Swiss cheese and then just completely disintegrated.

Have you had any changes recently? Poor water parameters should be considered too, along with predation by fish, inverts or parasites.